1. The Wii will be able to connect to that access point. It supports all the same encryption. I highly recommend using encryption on your wireless network.

2. Yes - it will work without a PC on. However, you will need a PC to set up the device.

3. No - it is not straightforward to use these with a normal modem. Although you could ge creative with linux, iptables, and autodialing on access, it's really not the best way. The device is intended for 24hr always-on broadband. Likewise, WiiConnect24 is designed for 24hr always on broadband.

If you're going to be using a PC and a dialup modem to connect, I suggest getting Nintendo WiFi adapter.